The predation rate per hour of Macrolophus pygmaeus Rambur (Hemiptera: Miridae) under light and dark phase was examined in relation to the host plant, photoperiod, temperature, and life stage of the predator. Individuals from each nymphal stage plus adults of both sexes of M. pygmaeus were put individually into petri dishes on an eggplant or pepper plant leaf infested with nymphs of Myzus persicae (Sulzer) (Homoptera: Aphididae). The experiments were conducted at three photoperiods (8:16, 12:12, and 16:8 h [L:D]) and temperatures (20, 25, and 30°C) on eggplant and pepper plants. Generally, the predation rate was significantly higher in the dark than in the light phase, particularly in the case of larger instars and adults. Interactions between factors showed that the preference of this predator to feed at night is much higher on pepper plants than on eggplant, and this difference is more prominent at 30°C. The importance of these results in understanding foraging behavior and how aspects of this behavior affect the predator’s potential in biological control are discussed.